1. Field of the Invention
This invention relates to the field of equipment and accessories for internal combustion engines, more particularly those supplied by high-pressure fuel rails.
The object of the invention is more particularly a functional module that integrates a distributor and a fuel rail as well as a process for the production of such a module.
In the vehicles with internal combustion engines, of which the different pistons are supplied by a common fuel rail, the latter is often located close to the distributor in the immediate surroundings of the engine, with these two accessories also having to be made rigidly integral with the engine block.
It was consequently obvious for one skilled in the art to attempt to connect these two accessories to one another so that they form a structural unit that has internal cohesion and can be made integral together with the engine block. Various solutions in this direction have already been formulated and presented.
2. Description of the Related Art
It has thus been proposed to mount the fuel rail on the distributor, for example by the document FR 2 779 681.
In this document, the two accessories are connected to one another by a quick-action coupling.
Nevertheless, an indirect attachment of the fuel rail on the engine block through the distributor is necessarily less rigid and less resistant than a direct attachment and also in addition stresses at least a part of said distributor, as well as its attachment points.
It has also been proposed to attach the distributor and the fuel rail in a combined manner at the same attachment points while ensuring a mechanical connection between the two elements.
Thus, the document EP 1 240 423 discloses a combined distributor-fuel rail unit in which said rail is provided with annular extensions in the form of blank holders that each fits tightly around a distributor pipe. These blank holders that are formed on the rail are equipped with tubular support feet for the passage of attachment screws, which line up with the openings for attachment of the connection plate of the pipes and that come into contact under pressure on said plate at said openings during the mounting on the engine block.
In another embodiment that is disclosed by this document, the blank holders are made of a single independent part that is not equipped with support feet, just covering the connection plate of the pipes and closing from the top the housing for receiving the rail in the plate.
In the two embodiments, the set of attachment points of the plate of the pipes and blank holders are combined, and the latter are not in direct support on the engine block, but rather rest on the plate that they make integral and flatten by clamping, also using the rail, against said engine block.
As a result, the attachment of the blank holders and the attachment of the pipes are totally interdependent, and the fuel rail itself participates in the mounting with locking of said pipes on the engine block.
Such a design nevertheless produces a complex structure for the fuel rail when it is formed integral with the blank holders.
In addition, these known embodiments impose a forced configuration for the connection plate of the pipes for the purpose of ensuring that the support feet of the blank holders and the attachment openings of the plate of the pipes line up completely. The result may be an implantation of the attachment sites of the connection plate that is not optimized in terms of strains and stresses, especially since this plate is assembled with the intake manifold, whose positioning in space of the main body can be shifted or offset relative to that of the plate.
Furthermore, stressing the fuel rail to participate positively in making the plate of the pipes integral on the engine block generates mechanical strains on this rail that can be detrimental over time to its structural integrity, taking into account in particular the vibratory context.
Finally, a forced disengagement of the plate of the pipes during disengagement or disassembly of the holding part may not be desirable in certain contractive configurations and may even be detrimental, for example in terms of time loss and problems during reassembly and/or sealing.